Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Qual unidade teve a construção iniciada em 01.07.1967?
 ###Tabelas: CREATE TABLE reactor_data (reactor_data_id AUTO_INCREMENT PRIMARY KEY, Unit VARCHAR, Reactortype VARCHAR, Net capacity VARCHAR, Gross capacity VARCHAR, Construction started VARCHAR, Electricity Grid VARCHAR, Commercial Operation VARCHAR, Shutdown VARCHAR) CREATE TABLE political_assistants (political_assistants_id AUTO_INCREMENT PRIMARY KEY, Romanised name VARCHAR, Chinese name VARCHAR, age at appointment INT, Foreign nationality VARCHAR, Portfolio attachment VARCHAR, Prior occupation VARCHAR, Govt salary VARCHAR) CREATE TABLE under-23_international_goals (under-23_international_goals_id AUTO_INCREMENT PRIMARY KEY, Date VARCHAR, Venue VARCHAR, Score VARCHAR, Result VARCHAR, Competition VARCHAR) CREATE TABLE character_appearances (character_appearances_id AUTO_INCREMENT PRIMARY KEY, Character VARCHAR, Played by VARCHAR, Season 1 INT, Season 2 INT, Season 3 INT, Season 4 INT, First Appearance VARCHAR) CREATE TABLE winners_from_2004 (winners_from_2004_id AUTO_INCREMENT PRIMARY KEY, Date INT, Category VARCHAR, Team VARCHAR, Rider 1 VARCHAR, Rider 2 VARCHAR)  
SELECT Unit FROM reactor_data WHERE Construction started = 01.07.1967